Photomasks are generally opaque plates with holes or transparencies that allow light to shine through in a defined pattern. They are commonly used in photoengraving and surface finishing processes to transfer a geometric pattern of light onto a light-sensitive chemical photoresist on a substrate surface. The substrate is then chemically treated to remove portions of the photoresist either exposed to light or not exposed to light, depending on the type of photoresist that is used. The patterned photoresist remaining on the surface of the substrate can then act as a mask during any of a number of surface treatment procedures, such as deposition, etching or blasting processes. After the photoresist is removed, the substrate surface is left with a pattern of treated and untreated regions.
In some cases, the substrate surfaces can include one or more surface features, such as designs and inlays. In some cases the features can be positioned on corners and edges. These surface features have borders that define the surface features. In a manufacturing environment where multiple similar parts are produced, the dimensions of the features can vary from part to part due to built-in tolerances of the manufacturing process. However, in traditional photomasking techniques the pattern imprinted on the photomask is fixed and does not accommodate any dimensional differenced of the features due to the manufacturing tolerances. This can ultimately lead to parts with surfaces having patterns of treated and untreated regions that mismatch the borders of the surface features. These mismatched borders can be noticeably cosmetically unappealing, especially if they are on exterior surfaces of a consumer product.